Ru(II) polypyridine complexes: photophysics, photochemistry, eletrochemistry, and chemiluminescence

Photoinduced motions in azo-containing polymers.

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

In the past few years, spiropyran has emerged as the molecule-of-choice for the construction of novel dynamic materials. This unique molecular switch undergoes structural isomerisation in response to a variety of orthogonal stimuli, e.g. light, temperature, metal ions, redox potential, and mechanical stress. Incorporation of this switch onto macromolecular supports or inorganic scaffolds allows for the creation of robust dynamic materials. This review discusses the synthesis, switching conditions, and use of dynamic materials in which spiropyran has been attached to the surfaces of polymers, biomacromolecules, inorganic nanoparticles, as well as solid surfaces. The resulting materials show fascinating properties whereby the state of the switch intimately affects a multitude of useful properties of the support. The utility of the spiropyran switch will undoubtedly endow these materials with far-reaching applications in the near future.

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Spiropyran-based dynamic materials

Photoalignment of Liquid-Crystal Systems.

Command surfaces of Langmuir-Blodgett films. Photoregulations of liquid crystal alignment by molecularly tailored surface azobenzene layers

Photochemical induction and modulation of nematic homogeneous alignment by the polarization photochromism of surface azobenzenes

Deposition de films 2B d'alcool polyvinylique modifie par greffage de chaines laterales comportant un groupe azo, sur des substrats de verre et intercalation d'un cristal liquide nematique entre 2 substrats ainsi modifies. Orientation du cristal liquide induite par photoisomerisation des groupes azo

Photochemical alignment regulation of a nematic liquid crystal by Langmuir-Blodgett layers of azobenzene polymers as "command surfaces"

Violet-blue emission from novel aromatic bis(diazaborole)s, which were synthesized by the reaction of 2,5-bis(hexyloxy)-1,4-phenylenediboronic acid and 1,2-phenylenediamine derivatives or diaminonaphthalene derivatives, is described. White-blue emission from a 4-methoxy-1,2-phenylenediamine-derived molecule was observed in DMF using 340 nm as the excitation wavelength.

Syntheses and emission properties of novel violet-blue emissive aromatic bis(diazaborole)s

Photoirradiation of a thin film of a homopolymer of 4-methacryloyloxyazobenzene with linearly polarized visible light, followed by cell fabrication, was found to generate a homogeneous alignment of nematic liquid crystals. In contrast, no alignment regulation was attained when the cell fabrication is made before photoirradiation, suggesting that the photo-induced persistent reorientation of the azo-chromophore is disturbed by penetration of the liquid crytal molecules into the polymer film to enhance the randomization of the oriented azobenzene chromophores

Yuji Kawanishi

Papers

Command surfaces of Langmuir-Blodgett films. Photoregulations of liquid crystal alignment by molecularly tailored surface azobenzene layers

Photochemical induction and modulation of nematic homogeneous alignment by the polarization photochromism of surface azobenzenes

Photochemical alignment regulation of a nematic liquid crystal by Langmuir-Blodgett layers of azobenzene polymers as "command surfaces"

Syntheses and emission properties of novel violet-blue emissive aromatic bis(diazaborole)s

Command surfaces, 6 Azimuthal orientation of liquid crystals photo-controlled by an azobenzene pendent polymer